Sorry about the lack of posts, I'm in the thick of the design stage at the moment.  As you can see from the calculations sheet, where I have the pivot point is obviously going to have a massive effect on what angle of movement I can get.  With the pivot point at the back, I can get 28.4° downwards before the nose hits the ground.  However, this is with the cockpit mounted 1m up.  With the pivot point in the centre, I can get 47.2° from 1m up.  On the other hand I could keep the 28.4°, but the cockpit would only have to be raised 50cm, making access much easier.  On the downside, this means finding a ball and socket bearing large enough to take the required loads, and working out how to attach the damn thing to the bottom of the cockpit!  Decisions, decisions!